Swallows Swallow Local Bugs

Filed in Birding, Expert Articles by on November 12, 2013

Walk outside on a sunny midsummer day and look skyward from an open vantage point. Chances are a swallow will fly through your field of vision within the first minute.

Swallows look like miniature fighter-jets gliding and soaring over open spaces. Zooming around at high speed, they gobble up insects with wide-open mouths. They’ll commonly circle back through a swarm of insects, and at times there are feeding frenzies with many swallows dive-bombing an especially thick cloud of the tiny winged prey.

TWG_story_birding16imgSwallow parents are now hard at work gathering insects to feed their fast growing chicks. This is a time of year when you can see the parents coming and going from the nest. Both mom and dad cruise for insects, store them temporarily in their esophagus, then return to the nest and regurgitate food to the hungry babies.

Eagle County is a great place to watch swallows, because six species of swallows summer here. Since swallows rely on fresh hatches of flying insects, they arrive here in early summer when consistent warm temperatures ensure regular insect hatches. It is common to see swallows lined up on a telephone wire on a frosty summer morning, because if it’s too cold for insects, there’s no reason for them to fly. Swallows will simply hang tight until the warm morning sun brings about another bounty of nutritious insects.

Swallows migrate north to Eagle County from as far south as Central America. Upon arrival, swallows search out open areas rich in flying insects and suitable nesting sites.

There is great diversity in the types of nests within the several species of swallows found here. For instance, the American tree swallow and the violet-green swallow require use of an old woodpecker nest cavity. Visit an aspen grove and look for neatly bored two-inch holes about ten to fifteen feet off of the ground. Without the woodpecker to make its home, these swallows would be left out in the cold.

Cliff swallows build gourd-shaped mud nests under overhanging rock cliffs, under the eaves of buildings, or under a bridge. Cliff swallows require a nearby quality mud source, which they scoop up by the mouthful, mix it with some special spit, and deposit it on their structure like a mason neatly laying tiny mud bricks. A thousand mouthfuls later, they have a perfect hanging clay home, with an entrance hole just large enough for the birds to come and go.

Readily observe cliff swallows visiting nests and feeding babies the next time you go to the Minturn Market. There are many fine nests under the eaves of the Cowboys and Indians building.

Like its cousin the cliff swallow, the barn swallow also requires mud to build its cup shaped nest on a ledge inside a barn, under a bridge, or on a cliff ledge. Barn swallows can be identified in flight by their long graceful forked tail.

Northern rough-winged swallows and bank swallows do not build, but rather excavate their nests in a sandy earthen bank. Visit a nearby river and look for a sandy cliff face with two-inch holes. These swallows tenaciously burrow in horizontally as deep as six feet, pecking with their bill, scratching with their feet, and removing the debris with their wings and feet.

Have you ever wished that the outdoors were insect free? We must remember the role that insects play in pollinating our colorful wildflowers, in feeding our marvelous variety of birds, and filling the bellies of the trout that grace our gold medal streams. Indeed insects make summer here in Eagle County as sweet as honey.

Tom and Tanya Wiesen are owners of Trailwise Guides; a year-round Vail Valley guide service specializing in hiking, mountain biking, and natural history tours. Daily private tours are available. Contact Trailwise Guides at (970) 827-5363.

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